The Phase Change Materials (PCM) are materials which absorb a great quantity of
energy during the change of phase solid /liquid and relies it during solidification
An application of these materials is thermal energy storage. The PCM integrated into
materials of the building can reinforce their inertia and reduce the power necessary for the
heating and air conditioning. This is particularly true for the buildings of the tertiary sector
whose envelope is light. Nevertheless, one of the characteristics which limits the use of the
PCM is their low conductivity.
The objective of this article is to propose a selection of materials having a
conductivity high enough to make it possible to ensure an air conditioning in summer
while limiting, even while removing, the use of energy (electricity or fuel) thanks to walls
containing these PCMs. This article consists of two parts:
- The first part exposes the problems of the study and specifies the context in which
the use of a PCM as a passive air conditioning system fits.
- The second part fixes the selection criteria which will allow, in a first approach to
choose certain materials.
When the temperature of the external surface of a wall increases, it is important to predict what the thickness of the wall will be so that the internal surface of the wall does not exceed a limit value. We will study, by an analytical method, the ca
se in which the external surface temperature is linearly varying with time in order to determine the time for which the temperature does not exceed a predetermined limit value at a given depth from the surface. Two cases will be considered: the first one is for a wall made of a homogeneous material (e.g. concrete) and the second one is for a wall made up of concrete and phase-changing material whose melting temperature will be selected according to the desired temperature. The results obtained show that a significant delay to reach this temperature can be obtained between the two cases.
